Dental-engine handpiece



, R.-c. CRAIG. DENTAL ENGINE HANDPIECE.

APPLICATION FILED JAN. 23, 192 0 Patented Dec. 21, 1920.

2 SHEETS-SHEET 1 I P i- 4 V IIVI/E/VTUR WITNESSES A TTOR/VEVS R. c. CRAIG. DENTAL ENGINE HANDPIECE.

APPLICATION FILED JAN-23, I920- Patented Dec. 21, 1920.

2 SHEETS-SHEET 2.

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Br 6 rm/mm #Wl T/VESSES PATENT OFFICE.

ROBERT CLAUDE CRAIG, or FABINGDON, VIRGINIA.

DENTAL-ENGINE imnnrmon.

Specification of Letters Patent. Pate ted B 21 1920 Application filed January 23, 1920. 1 Serial No. 353,445. 7

To all whom it may concern: a

Be it known that I, ROBERT C. CRAIG, a citizen of the United States, and residentof Abingdon, in the county'oflVashington and State of Virginia, have invented certain new and useful Improvements in Dental-Engine Handpieces, of which the following is a' specification. I v

My invention relates to hand pieces for dental engines, and a purpose of my invention is the provision of a hand piece of simple, durable and efficient construction, including a clamp for effectively securing a tool therein so as to prevent its accidental displacement and to securely lock the same to the engine shaft for positive rotation therewith.

It is also a purpose .of my invention to provide a hand piece having means for. ad-

justing the tool clamp while the tool is rotated, such means being capable of maintaining its adjustmentthrough frictional contact without screws or other additional means.

I will describe one form of hand piece embodying my invention and will then point out in claims the novel features thereof.

In the accompanying drawings Figure 1 is a view showing in side elevation one form of hand piece embodying my invention in applied position upon the end of an engine shaft.

Fig. 2 is a view similar to Fig. 1 showing the hand piece detached from the engine shaft and the casing removed.

Fig. '3 is a view similar to Fig. 2 but taken at right angles thereto. I

Fig. 4 is; a longitudinally sectional view of Fig. 2. i

Fig. 5 is a transverse sectional view taken on the line 55 of Fig. 4E. V

Figs. 6, 7, 8 and 9 are detailed views of certain parts comprised of the hand piece shown in the preceding views.

Similar reference characters refer to similar parts in each of the several views.

Referring v specifically to the drawings and particularly to Fig. 1,0 designates a tubular casing in whichis rotatably mounted a spindle designated generally S, such spindle being connected at its upper end to the shaft of the dental engine (not shown) which is incased in a sheath H. As illustrated to advantage in Fig. 8, the lower end of the spindle S is of conical formation and is bored longitudinally to receive a standard form of dental tool T, as shown in Fig.7

4. Above the conical end, the spindle S is provided with a longitudinally extending slot 15 which communicates with the bore of the conical end so that'the shank of the tool T extends into the slot. As shown in Fig. 1,'the slot 15 is adaptable to receive a pair of clamping members K and K which are provided with ears 16 and 7 16 respectively formed-with openings to loosely receive a I pintle 17. As shown in Fig- 3, the pintle 17 is securelyfitted within suitable openings formed in the spindle S so that it spans the slot 15 and provides an axis about which the clamping members K and K are adapted to circular shank of the tool T; Adjacent the ear 16, the gripping portion 18 is formed with a recess 20, while the gripping portion 18 is formed with a lug 21 adjacent the pivot car 16*. The'purpose of the recess 20 and the projection 21 is to accommodate the tang of the tool T whichis shown in Fig. 4 as semi-circular and provided with a notch for the reception of the lug 21. As a result of this arrangement, the gripping portions 18 and 18 coact to effectively secure the tool T within the spindle S.

The expanding portions 19 and 19 of the members K and K are provided upon the inner sides with inclined surfaces 22 which are adapted to be engaged by a pair of expanding arms A and A for spreading or contracting the portions to effect a movement of the'gripping portions to clampin or releasing positions. As shown in Figthe arms A and A slidably engage the flattened por-' tions 23 of the spindle S and are provided upon their uter sides with grooves 24 which gradually increase in depth from their upper ends to their. lower ends to provide inclined surfaces which are adapted to coact with the inclined surfaces 22 of the expanding portions 19 and 19 By this arrangement it will be seen that when the arms A and A are'moved the tool.

. varied.

the gripping portions 18 and 18 into snug.

engagement with the shank of the tool T. By moving the arms upwardly from this position, it is obvious that the gripping portions 18 and 18 are free to disengage thetool shank so as to permit'the ready removal of The arms A and A are integrally connected at the upper ends by a collar 25 which is formed with an annular groove to receive the lower ends of a pair of resilient fingers 26 and 26, the upper ends of such fingers being permanently securedat diametrically opposite points to a cylindrical head 27 that loosely embraces the spindle S so that the latter isfree to rotate independentlyof the same. To prevent lateral displacement of the fin ers 26 and 26 I provide a guiding yoke 2% as shown to advantage in Fig. 5 is of annular formation and is provided at dia metrically opposite points upon its periphery with grooves for the reception of the fingers 26 and 26 This yoke 28 is free to rotate about the spindle S which is fixed to a sleeve 29 by a pair of screws, 30. The yoke 28 is locked against longitudinal movement upon the spindle S by a pair of collars-31 and 31* which are fixed to the spindle by screws 32 so as to engage the opposite sides of the yoke, as clearly shown in Fig. 4. As shown in this latter figure, the sleeve 29 loosely embraces the head 27 so that'the latter is free to move longitudinally on' the spindle S and independentl of such sleeve.

As shown in Fig. 1, the upper portion of the sleeve 29 constitutes a continuation of the casing C and rigidly supports the latter by means of a screw 33 which extends through the casing and engages the lower portion of the sleeve 29, as will be understood.

'As shown in Figs. 1 and 9, the upper end ofthe casing C is recessed to accommodate a relatively small screw D, the head of which is interposed between the sleeve 29 and the upper edge of the casing C so that by adjusting the screw longitudinally the position of the casin with respect to the sleeve maybe he purpose of this adjustment is to prevent the spindle jaws fitting too tightly within the tapering nose of the casing C; the set screw can be fed outwardly thus forcing the casing downwardy and thus withdrawing the casing a sufiicient distance from the jaws to allow the proper operation of the latter. On the other hand, as the jaws do not extend a sufiicient distance into the nose of the casing so as to operate properly the casing can be moved upwardly byfeeding the screw downwardly, it being understood that in both instances it is necessary to first unscrew the set screw 33. v

In practice, the gripping members K and K- are moved to engage or disengage the tool T by thearms A and A as has been previously described. The arms A and A are slid longitudinally upon the spindle in one direction or another by the fingers 26 and 26 the latter being actuated through the medium of the head 27 Because of the inclined surfaces formed on the arms A and A and the members K and K, it will be clear that suflicientfrictional contact is provided between these inclined surfaces to maintain the gripping members in any adjusted position so that thenecessity of employing additional means such as cams or screw-threaded collars, is eliminated.

Because of the manner in which the fingers 26 and 26' are connected to the arms A and A, it is obvious that the arms are free to rotate independently of the fingers so that -the latter may be moved to effect an adjusting my invention, it is to be understood that various changes and modifications may be made herein Without departing from the spirit of the invention and thespirit and scope of the appended claims.

Having claim is:,

1. A dental hand piece comprising a spindle havinga longitudinal slot formed therein in which a tool is adapted to be inserted, a'pair of gripping members disposed described my invention, what I within said slot and pivoted upon a-single axis, each of said members comprising a gripping portion at one side of the plvot and an expanding portion at the opposite side thereof, an expanding member slidable" longitudinally on said spindle and comprising arms having grooves formed therein to slidably receivesaid expanding portions, a

grooved collar connected to saidarms and slidable upon said spindle, a pair of resilient fingers working within said collar, and

a head supporting said fingers and slidable on said spindle to actuate said fingers independently of said'spindle for effecting a movement of said arms, the walls'in saidgrooves and the confronting faces of said expanding portions being inclined-to eflect a contraction or expansion of the gripping portions upon movement of said arms.

2. A dental hand piece comprising a spindle bored to receive a tool, a pair of gripping members pivoted in said spindle, arms slidable on said spindle, said arms and gripping members being provided with inclined ,surfaces to effect an expansion or contraction of the gripping members according as the arms are moved in one direction or the other, a grooved collar carried by said arms and slidable on said spindle, a pair of resilient fingers engageable With said collar, a head slidable on said spindle and supporting said fingers, a guiding yoke loosely engaged in said spindle and having grooves therein to receive the intermediate portions of said fingers, and

collars secured to said spindle 10 OBERT CLAUDE CRAIG. 

